Abstract

Despite the pervasive use of idealizations and approximations in science, the issue of their role has been neglected or misunderstood by philosophers. Idealizations enter into a scientific analysis or explanation in at least two ways. First, they may be embodied in the very statement or formulation of laws and theories; I call such laws idealizational laws. Second, they may be conjoined to a theory as extraneous assumptions, mainly to make it easier to work with the theory. I first examine the problems of testing pertaining to idealizational laws. I argue that the major theories of confirmation face difficulties in accounting for the confirmation and disconfirmation of such laws. Underlying their difficulties is the fact that those laws are about nonexistent objects. The analysis I propose of the testing of idealizational laws is based on the fact that idealized objects comprising the domains of such laws can be approximated by real objects. ;I next investigate the problems of testing in relation to theories and hypotheses which are fed idealizational assumptions and approximations from outside. In the course of my discussion of the issues surrounding the use of idealizations and approximations in science, I critically examine the views of Milton Friedman, Clark Glymour and Ronald Laymon. In the final chapter I propose an analysis of confirmation which is within the Bayesian tradition. My analysis, if correct, is an improvement over the standard Bayesian framework in two respects. First, it is a more realistic representation of the testing process in actual science. Secondly, it is capable of solving "the problem of old evidence," which has recently troubled traditional Bayesianism. Both of these advantages my analysis achieves by taking as the evidence not the observation itself, but the error or discrepancy between the observation and what was predicted by the theory in conjunction with the idealizations and approximations. ;In the Appendix I argue against a prevalent view among physicists and philosophers of science concerning the interpretation of the domain of Newton's second law, viz. the view that the domain of this law, when properly stated, consists of point-masses